CLEVELAND -- You are being tracked.

And you can't hide from cops with license plate scanners.

Police across the U.S., and right here in Ohio, are using automatic cameras to read and snap digital photos of millions of license plates, but, in the process, they're storing information on millions of innocent people.

Imagine this, you're driving down the highway. You think you're alone.

But Big Brother and the Ohio State Highway Patrol are with you, watching.

In fact, if you're driving by Sgt. Timothy Timberlake, you'll have three sets of eyes on you, his and two sets from these mounted cameras.

"It's impossible for me to check every car that goes by," says Timberlake.

But nothing escapes these innocuous looking eyes.

They're actually cameras, working like searchlights to scan your license plate.

If you're within a certain radius of Timberlake's car, your plates will get scanned and checked against a database that logs outstanding warrants and stolen vehicles.

Moving or parked, these high speed cameras can scan thousands of plates, up to 7,200 an hour.

When these eyes scan a license plate that's attached to a warrant or a stolen vehicle, the computer system alerts Timberlake with an auditory cue.

While riding with Timberlake in Cleveland, Channel 3 heard got several "hits" on the scanners: a man with an outstanding warrant, and a call for a 75, also known as a stolen vehicle.

"It helps to deter the crime, and it helps us recover cars. It takes that off the streets and out of the communities," says Timberlake.

But what about the information gathered from law abiding citizens?

This system doesn't discriminate.

When your plates get scanned, that info is stored in a database.

"Our real concern is around how long the data is kept and with whom it is shared," says Melissa Bilancini with the Cleveland American Civil Liberties Union.

She believes public safety shouldn't mean compromising individual privacy.

"But really, it's the keeping of information of people who've not done anything wrong. That is a concern of ours," says Bilancini.

So Channel 3 decided to dig a little deeper into the issue of your privacy.

Here's what we uncovered: When it comes to the State Highway Patrol, "All 'non-hit' captures shall be deleted within a 24-hour period."

It further specifies that license plate reader "captures" shall not be collected, stored or shared with the intent of data mining."

Meaning your digital trail can't be tracked.

"The Ohio State Highway Patrol actually has a really great policy for this," says Bilancini.

But the same can't be said for other departments throughout the state.

According to a national ACLU report, the Franklin County Sheriff's Office keeps that data for 90 days.

And other departments don't have any policy at all, meaning your private information could be lost, shared or even stored on some computer indefinitely.

Which is why, right now, the ACLU is fighting for statewide legislation.

They'd like to see every law enforcement department following the same policy -- preferably a policy that purges your info within 24 hours.

The State Highway Patrol began using the license plate scanners back in 2004.

And, we're told, they had significant success on the Ohio Turnpike.

The scanners are now used primarily in stationary locations on the turnpike and on 11 mobile units that are deployed throughout the state.